Fix layer cache memory leak

src/gpu/GrLayerCache.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAtlas.h"
 #include "GrGpu.h"
 #include "GrLayerCache.h"
@@ skipping 76 matching lines @@
 GrLayerCache::~GrLayerCache() {
 
     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         GrCachedLayer* layer = &(*iter);
         SkASSERT(0 == layer->uses());
         this->unlock(layer);
         SkDELETE(layer);
     }
 
+    SkASSERT(0 == fPictureHash.count());
+
     // The atlas only lets go of its texture when the atlas is deleted. 
     fAtlas.free();    
 }
 
 void GrLayerCache::initAtlas() {
     SkASSERT(NULL == fAtlas.get());
     GR_STATIC_ASSERT(kNumPlotsX*kNumPlotsX == GrPictureInfo::kNumPlots);
 
     SkISize textureSize = SkISize::Make(kAtlasTextureWidth, kAtlasTextureHeight);
     fAtlas.reset(SkNEW_ARGS(GrAtlas, (fContext->getGpu(), kSkia8888_GrPixelConfig,
@@ skipping 159 matching lines @@
         // This testing code aggressively removes the atlased layers. This
         // can be used to separate the performance contribution of less
         // render target pingponging from that due to the re-use of cached layers
         GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
         SkASSERT(pictInfo);
 
         pictInfo->decPlotUsage(plotID);
 
         if (0 == pictInfo->plotUsage(plotID)) {
             GrAtlas::RemovePlot(&pictInfo->fPlotUsage, layer->plot());
+
+            if (pictInfo->fPlotUsage.isEmpty()) {
+                fPictureHash.remove(pictInfo->fPictureID);
+                SkDELETE(pictInfo);
+            }
         }
         
         layer->setPlot(NULL);
         layer->setTexture(NULL, GrIRect16::MakeEmpty());
 #endif
 
     } else {
         layer->setTexture(NULL, GrIRect16::MakeEmpty());
     }
 
@@ skipping 149 matching lines @@
     GrAtlas::PlotIter iter;
     GrPlot* plot;
     for (plot = fAtlas->iterInit(&iter, GrAtlas::kLRUFirst_IterOrder);
          plot;
          plot = iter.prev()) {
         SkASSERT(0 == fPlotLocks[plot->id()]);
 
         this->purgePlot(plot);
     }
 
+    SkASSERT(0 == fPictureHash.count());
+
     fContext->discardRenderTarget(fAtlas->getTexture()->asRenderTarget());
 }
 #endif
 
 class GrPictureDeletionListener : public SkPicture::DeletionListener {
     virtual void onDeletion(uint32_t pictureID) SK_OVERRIDE{
         const GrPictureDeletedMessage message = { pictureID };
         SkMessageBus<GrPictureDeletedMessage>::Post(message);
     }
 };
@@ skipping 36 matching lines @@
             continue;
         }
 
         SkString fileName(dirName);
         fileName.appendf("\\%d-%d.png", layer->fKey.pictureID(), layer->fKey.start());
 
         layer->texture()->surfacePriv().savePixels(fileName.c_str());
     }
 }
 #endif